Missile systems, such as the Theatre High Altitude Area Defense (THAAD) ballistic missiles, use hypergolic fuels and oxidizers as a means of propulsion. These hypergolic propellants and oxidizers are corrosive, carcinogenic, toxic, and present fire hazards when a leak is present. Their storage and deployment is thus crucial to ensure personnel safety and mission success. The hypergolic fuel used in missiles is hydrazine or monomethyl hydrazine (MMH), and the oxidizer used in missiles is mixed oxides of nitrogen (MON-25) that is a mixture of dinitrogen tetroxide (N2O4), nitrogen dioxide (NO2) and nitric oxide (NO). N2O4 is a dimer of NO2. Under equilibrium conditions, nitrogen tetroxide (NTO) exists as a mixture of N2O4 and NO2. Therefore, detection of MMH as a hypergolic fuel and NO2 as an oxidizer would indicate a leak in the system.
Electrochemical, chemiluminescence, chemical resistance, absorption, and fluorescence-based detection systems have been developed for the detection of hypergolic fuel and oxidizer leaks. However, these leak detecting sensor devices suffer from drawbacks such as lack of specificity, less effective operation at elevated temperatures, and cell leakage problems leading to maintenance challenges. In addition, the prior art electrochemical monitoring devices can operate in the range −20° C. to +71° C. However, the response time of prior art electrochemical systems at −20° C. is typically 55 minutes at 100 ppm for NO2, and their sensitivity is typically about 100 ppm for both MMH and NO2. Prior art systems also should be replaced annually—which is a maintenance burden and drives system lifecycle costs. Thus, the development of a highly reliable and accurate transducer element to detect rapid changes in concentration of hypergolic fuels and oxidizers within a tactical leak detection subsystem is desired.
Atmospheric levels of carbon dioxide (CO2) have risen significantly from pre-industrial levels of 280 ppm to present levels of 384 ppm. Predictions on future energy use indicate a continued increase of atmospheric CO2 unless major changes are made in the way energy is produced and how carbon is managed. Due to current concerns about global climate change related to increased CO2 emissions, efforts are underway to better utilize both terrestrial and geologic CO2 sinks as forms of carbon management, offsetting emissions from fossil fuel combustion and other human activities. The storage of industrially generated CO2 in deep geologic formations is considered a viable method and important for reducing CO2 (green house emissions) from the atmosphere. Roughly a billion metric tons of CO2 has to be sequestered annually to make an impact. The Department of Energy (DOE) carbon sequestration “Monitoring Verification and Accounting (MVA)” program requires sensors to monitor, measure and account for 99% of CO2 in the injection zones to confirm safe and permanent storage of CO2 in geologic formations, especially in the near-surface and subsurface environments over a large area with improved accuracy and long-term durability. Reliable and cost-effective monitoring systems are critical to safe permanent storage. Light Detection and Ranging (LIDAR) or satellite-based technologies are only effective for atmospheric or above ground CO2 monitoring. By the time leaked CO2 appears above the surface, significant damage may have occurred to ground water and the surrounding ecosystem. Therefore, a reliable and cost-effective near-surface/subsurface CO2 monitoring system is critical to confirming the safe and permanent storage of 99% of CO2 in the geologic injection zones.
Alzheimer's disease (AD) is the most common form of dementia. AD and other forms of dementia impose a tremendous financial burden on the health care system and the general economy. According to the Alzheimer's Association, the cost of caring for AD patients is estimated to be $203 billion in the United States in 2013. In addition, 15.4 million Americans provide unpaid care valued at $216 billion for persons with AD and other dementias. Unless addressed, the cost of AD is estimated to reach $1.2 trillion by 2050. Therapeutics can delay the onset of AD to an extent; however their efficacy depends on early diagnosis. In 2012, the U.S. Food and Drug Administration (FDA) approved Amyvid, a radiopharmaceutical imaging agent for positron emission tomography (PET) scans that measure the brain β-amyloid plaque density in-vivo in patients. The PET scans are highly sensitive. However, Amyvid PET scan is not a test for predicting the development of AD-associated dementia and is not intended to monitor patient responses to AD therapy. Amyvid does not replace other diagnostic tests used in the evaluation of cognitive impairment. In addition, PET scans are costly, time consuming, require skilled personnel, and cannot be used as a point-of-care application in doctor's offices and clinics. Another diagnostic method based on a flow cytometric test of Aβ phagocytosis for the detection of AD biomarkers in blood was reported. Neither of these approaches can easily be converted into a cost-effective diagnostic or research tool. Despite the utmost importance, no cost-effective biosensor technologies have been marketed to detect AD biomarkers. Therefore, there is an urgent need to develop technologies for AD screening and early presymptomatic diagnosis. Developing a simple and low-cost biosensor for reliable early diagnosis of AD in point of care facilities is needed.
Cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells. It is the leading cause of death worldwide. The United States National Cancer Institute Society has estimated that there are 1,444,920 new cases of cancer and about 559,650 deaths in the United States each year—more than 1500 deaths per day. The National Institutes of Health estimates that the overall costs for cancer in each year are $206.3 billion: $78.2 billion for direct medical costs; $17.9 billion for indirect morbidity costs; and $110.2 billion for indirect mortality costs. This problem underscores the need for reliable and cost-effective methods for early detection and diagnosis of cancer. A device to monitor cancer therapy progress is also needed. There are several different kinds of cancer. For example: (i) Prostate cancer (PC) is the most common type of cancer found in American men. The American National Cancer Society estimates that there are 218,890 new cases of PC and 27,050 deaths in the United States in each year. PC is the second leading cause of cancer death in men in the United States. Prostate specific antigen (PSA) is the over-expressed biomarker of PC, and is crucial for the detection and diagnosis of PC. (ii) Breast cancer (BC) is the most frequently diagnosed cancer in women. The American National Cancer Society estimates that there will be about 240,510 new cases of breast cancer among women and, as estimated, 40,910 breast cancer deaths (40,460 women and 450 men) are expected in the United States each year. BC ranks second among cancer deaths in women. A protein called human epidermal growth factor receptor 2 (HER-2/neu) is overexpressed in about 20-30% of BCs, which tend to be more aggressive. This overexpressed HER-2/neu protein is an important therapeutic target/biomarker for diagnosis and prognosis of BC. (iii) Lung cancer (LC) accounts for the most cancer related deaths in both men and women. An estimated 213,380 new cases and 160,390 deaths, accounting for about 29% of all cancer deaths, are expected to occur in the United States in each year. Epithelial cell adhesion molecule (EpCAM) protein is an important biomarker of LC. A primary cause of poor survival rates is that many cancers are detected late, after they have spread or metastasized to distant sites. For most types of cancer, the earlier the detection the greater the chances of survival. Therefore, there is an urgent need for devices or methods that can accurately and reproducibly measure multiple cancer biomarkers or circulating tumor cells in bodily fluids or other specimens obtained by minimally invasive methods.